Conventional techniques for reducing rolling resistance of a tire include those disclosed in Patent Literature 1, Patent Literature 2 and the like. The invention disclosed in Patent Literature 1, which aims at providing a pneumatic tire capable of reducing rolling resistance without sacrificing stability, controllability and riding comfort, is characterized in that: a fold-back end of a carcass is positioned at the height of ≦0.15 time the height SH of the tire section; and a short fiber reinforced layer of ≧0.3 mm and ≦1.0 mm in thickness is arranged on the outer surface of the carcass in a sidewall area between a belt end and the fold-back end of the carcass. The short fiber reinforced layer is constituted of: a rubber component obtained by blending 30-60 parts by weight of natural rubber and/or isoprene rubber with 40-70 parts by weight of butadiene rubber; short fiber; and carbon black. At least 90% of the short fiber is oriented at an angle in the range of ±20° relative to the circumferential direction of the tire and the ratio of the complex elasticity E*a in the direction of orientation of the short fiber, with respect to the complex elasticity E*b in the direction orthogonal to the direction of orientation, is ≧5.
Further, the invention disclosed in Patent Literature 2, which aims at providing a pneumatic tire capable of making weight reduction and good stability and controllability thereof compatible without reducing riding comfort, is characterized in that: a carcass layer is made to be a single layer structure; ends of the carcass layer are each folded around a bead core from the inside toward the outside of the tire to interpose a bead filler therein, to a position which exceeds a tire maximum width and does not reach a belt layer; and the height of the bead filler measured from a bead heel is 15-30% of a tire cross section height SH, the rubber thickness of a sidewall portion is 3.5-5.0 mm, an inner liner is formed of a thermoplastic elastomer composition having Young's modulus of 5-50 MPa and thickness of 0.05-0.25 mm, and the sidewall portion is made of a rubber composition containing at least 70 wt. % of natural rubber.